pulp morphology 2 Flashcards
what are the functions of the odontoblast layer as a permeability barrier?
separates pulp and tubular space
regulates movement of material between pulp and tubular ECF
movement can be in either direction
what is exchanges from pulp to dentine?
nutrients
secondary and tertiary dentine
tubular nerves i.e potassium
what is exchanges from dentine to pulp?
medicaments applied to dentine
diffusion of toxins from bacteria or components of filling materials
what are pulp nerves branches of?
alveolar nerves
where do the nerves enter the pulp?
neurovascular bundles enter pulp via apical foramen
what is the journey of the pulp nerbes?
pass along root canal in centre of pulp towards coronal pulp chamber, branch out in sub-odontoblastic layer
(rashow’s plexus)
terminal branches enter odontoblast layer, some enter dentinal tubules
describe the innervation of dentine
40% of nerves enter tubules
15% tubular innervation in coronal dentine
4% root dentine
most axons end in pulp-predentine region so don’t enter tubules
what is the function of the hydrodynamic mechanism?
activating intradental sensory nerves
what stimulus can start the hydrodynamic mechanism?
thermal, mechanical, evaporative, chemical
what does the hydrodynamic mechanism stimulus act on?
exposed dentine; open tubules
describe the hydrodynamic mechanism
the stimulus on exposed dentine increases rate of dentinal fluid flow
generating AP’s in intradental nerves
AP’s pass to brain to cause pain
what are the effects of outward fluid flow?
cooling drying evaporating hypertonic solutions decreased hydrostatic pressure
what are the effects of inwards fluid flow?
heating
mechanical
increased hydrostatic pressure
which direction of fluid flow is more effective in activating intradental nerves?
outwards (away from pulp)
as rapid, outward flow stretches the nerves
which stimuli bypass the hydrodynamic mechanism and act directly on intradental nerves
intense heat
intense cooling
electrical current
pain-producing chemicals